Fig. 2.

O₂ uptake by N₂-fixing filaments and heterocysts of the WT and mutant strains. (A) MIMS measurements of O₂ consumption during the dark-to-light transition by whole filaments of the WT (solid line) and mutants: ∆flv1B (dotted line), ∆flv3B (dashed line), ∆flv1B/3B (dash-dot line). (B) O₂ uptake by WT heterocysts with or without inhibitors. (C) Light-induced O₂ uptake by WT and ∆flv3B heterocysts; dark O₂ uptake rates were subtracted for better legibility. Arrows indicate the beginning of illumination. Chl a content of samples was adjusted to 15 μg⋅ml⁻¹.